Nest Full of Baby Dinosaurs Found

Below:

Next story in Science

A 70-million-year-old nest of the dinosaur Protoceratops
andrewsi has been found with evidence that 15 juveniles were
once inside it, according to a paper in the latest Journal of
Paleontology.

While large numbers of eggs have been associated with other
dinosaurs, such as the meat-eating Oviraptor or certain
duck-billed hadrosaurs, finding multiple juveniles in the same
dino nest is quite rare.

"I, for one, cannot think of another dinosaur specimen that
preserves 15 juveniles at its nest in this way," lead author
David Fastovsky told Discovery News.

Fastovsky, who is chair of the University of Rhode Island’s
Department of Geosciences, and his colleagues analyzed the
dinosaur remains along with the nest, which measured about 2.3
feet in diameter and was round and bowl-shaped. All were found at
Djadochta Formation, Tugrikinshire, Mongolia, where it's believed
sand “rapidly overwhelmed and entombed” the youngsters while they
were still alive.

The researchers conclude that the 15 dinosaurs all show juvenile
characteristics. These include short snouts, proportionately
large eyes, and an absence of adult characteristics, such as the
prominent horns and large frills associated with adults of this
species. At least 10 of the 15 fossil sets are complete.

The nest and its contents imply that Protoceratops
juveniles remained and grew in their nest during at least the
early stages of postnatal development. The nest further implies
that parental care was provided.

The large number of offspring, however, also suggests that
juvenile dinosaur mortality was high, not only from predation,
but also from a potentially stressful environment.

"Large clutches may have been a way of ensuring survival of the
animals in that setting -- even if there was extensive parental
care," Fastovsky said. "Mongolia was, at the time, a place with a
variety of theropod dinosaurs, some of whom likely ate babies
such as these."

"The most obvious of these, found in the same deposits, is the
(in)famous Velociraptor, a smallish nasty theropod with
bad breath, for whom babies such as these would have made a nice
bon bon," he continued.

Yet another discovery previously found at the same locality is
the famous "fighting dinosaurs" specimen in which a
Protoceratops and Velociraptor appear to have
been preserved together "locked in what was evidently mortal
combat," Fastovsky added. Parents and other adults of the
sheep-sized herbivorous species may then have spent much of their
time fighting off such hungry predators.

In a separate study, Lars Schmitz of the UC Davis Department of
Evolution and Ecology, and colleagues studied bones surrounding
what would have been the eyes of Protoceratops and other
dinosaurs. The results allowed Schmitz and his team to conclude
that this dinosaur and additional plant eaters were active both
day and night. Velociraptor, on the other hand, was
primarily a nocturnal carnivore, so night raids on
Protoceratops nests must have taken place during the
Late Cretaceous.

Even if the juvenile dinosaurs and their parents "had a good
sensory system to notice a predator closing in, the success rate
of a nocturnal attack may be higher than a diurnal attack,"
Schmitz told Discovery News.

Given the chances then of literally biting the (sand) dust or
becoming dinner, it’s no wonder that some small dinosaurs had so
many kids.

"This story certainly isn't your parents'
dinosaurs-living-in-the-lush-Cretaceous-steaming-jungles that was
in vogue a generation or two ago," Fastovsky said. "We now know
that dinosaurs lived everywhere and did just about everything
terrestrial."

The nest and its dinosaur family contents are currently housed at
the Paleontological Center of the Mongolian Academy of Sciences,
Ulan Baatar, Mongolia.